Cryogenic rocket propellant tank is a pressure vessel for storing fuel or oxidizer of rocket stages. Generally, Liquid Hydrogen is used as fuel for cryogenic stages. The Fuel is stored at very low temperature at 20 K. Vibration analysis of cryogenic propellant tanks is significant in addition to the pressure analysis. Intense of vibrations are high during start and shut down of the rocket engine. The vibration levels generate major problems in propellant tank and its internals. Hence estimating the frequency levels at various possible modes is essential. Design and modal analysis of the Liquid hydrogen propellant tank is carried out in ANSYS workbench 15.0 in this work. Frequencies at six mode variations are taken and frequency ranges are compared.